基于有限元法的轿车后门刚度分析

车门的静态刚度是判断车门结构是否合理的重要指标之一。文中以某款中级轿车的后车门为模型,建立车门有限元模型,利用有限元法在MSC．Nastran中对后车门进行刚度分析,获得后车门刚度薄弱部位,并对后车门的结构进行改进：整个静态刚度分析将为车门结构设计与优化提供理论依据。     

汽车前车门结构性能的计算机辅助分析与研究

通过计算机辅助分析与计算，建立车门有限元计算模型，全面分析车门在各种可能工况下的应力、变形和模态特性等各项性能，以确定车门结构设计的合理性、可靠性是满足各项技术性能要求。为车门结构设计与优化提供思路与依据。     

车门静态强度的有限元分析模拟

轿车门系统结构设计与优化是整车开发过程中的重要环节。车门的强度直接关系到整车在冲击、碰撞等载荷下的安全问题,车门结构静态强度的计算分析,在车门结构设计进程中非常重要。文中首先简要介绍了静态强度所涉及到的非线性有限元的基本理论,然后以某中高级轿车前车门为例,利用计算机辅助分析车门的静态强度,考虑变形的非线性因素,通过对车门的非线性有限元求解来分析车门强度,由计算所得到的车门强度性能指标来指导车门的结构设计。     

外摆式车门的结构分析

车门是车身结构中一个较复杂的总成,车门结构设计是车身结构设计中的一个重要部分。熟悉车门结构的功能要求、结构特点是车门结构设计的基础。在具体的结构设计过程中,正确的方法、步骤是实现合理设计的关键,本文分析了外摆式车门的结构、工作原理及确定四连杆机构的方法,并简述其密封结构。     

汽车前车门下沉刚度的建模和分析

车门是车身结构的重要组成部分,其性能的好坏直接影响该车结构性能,也影响消费者对车的评价.轿车是属M1类车型,在我国拥有广泛的市场,以某轿车为例,依据国标对M1类试验标准,通过计算机辅助分析和计算,全面分析了其前车门下沉工况及结构部件的弯曲变形和应力分布,以确定该车门结构设计的合理性、可靠性以及是否满足各项技术性能的要求,为车门结构设计和优化提供思路和参考依据.     

车门玻璃下位振动传递路径建模及优化分析

阐述了传递路径分析(transfer path analysis,简称TPA)方法的基本理论,对某车型左前车门玻璃下位关门过程中玻璃振动异常进行了传递路径分析,并针对该车门结构设计特点,提出了基于传递路径分析方法的二级TPA分析模型,分别为锁机、密封条-玻璃一级传递路径模型和导轨接附点-玻璃二级传递路径模型.通过常用关...     

轿车后车门有限元分析

建立后车门分析的有限元分析模型,对后车门在自由状态下进行模态分析;在四种工况下对后车门的扭转刚度进行分析;在四种工况下对后车门进行下垂刚度的分析,通过CAE分析,为结构设计选择及结构优化提供了理论依据.     

基于灵敏度及尺寸优化的汽车车门轻量化

以国产某小车车门为研究对象,建立车门有限元模型,对车门进行垂直、侧向刚度分析,并进行自由模态分析和模态试验,验证模型的有效性。计算各部件对车门刚度和一阶模态的灵敏度,确定敏感区域。基于灵敏度分析方法,以车门质量最小为目标函数,在保证车门刚度和一阶模态频率不降低的前提下,结合尺寸优化设计方法优化车门各部件厚度。优化结果表明,车门下沉刚度提高了12.03%,水平刚度提高了1.04%,一阶模态频率提高了0.2 Hz,车门的总质量下降了4.74%,达到了良好的轻量化效果。     

基于有限元的汽车车门静态强度刚度计算与分析

随着科技的进一步发展,产品在趋于多样化、智能化的同时,也趋于复杂化。在新车型的开发设计过程中,如何判断车门结构的合理性及车门结构静态强度和刚度,是一项十分重要的工作。以南京IVECO某车型的前车门为例,在Pro/E中进行三维建模和模型的简化,在HYPERMESH中进行网格划分,并利用HYPERMESH与ANSYS接口,对车门进行静力学分析,计算车门刚度和强度较大和较小的位置,对车门设计具有一定的参考作用。     

乘用车车门异响分析及焊点优化

乘用车车门异响是影响车内舒适性的主要因素之一,而使得车门结构产生异响的主要因素是结构连接处焊点强度不足。以国内某乘用车车门为例,首先在CATIA中建立三维模型,基于有限元分析软件Hyper Mesh进行网格划分和模态分析,获得车门自由模态频率和振型;然后利用声学分析软件VAOne对车门异响进行有限元仿真分析,获取车门产生异响的主要分布区域。最后,基于拓扑优化方法对车门结构中的焊点布置进行优化设计,经焊点优化后的车门异响问题得到了有效解决。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.